This invention relates to printing, and in particular to preparing a layout for printing on a sheet or roll when the layout contains repeating designs.
This invention is most useful for printing packages and labels. A package is a container such as a box on which an image may be directly printed. The package is made from some medium that is provided in sheet form or roll form. The medium is then printed directly according to a layout, and is then trimmed or cut. The printed package is formed by a combination of one or more of folding, bending, and joining. Examples of packages include but are not limited to cereal boxes, cardboard cartons, milk cartons, potato chip bags, and soft drink cans.
A label in the context of this invention is a printed cut out piece of sheet-shaped medium that is attached to a container. Examples include wine labels attached onto wine bottles, plastic shrink wrap wrapped around plastic soft drink bottles, and paper labels on soup cans. While some labels are cut in rectangular form (xe2x80x9csquare-cutxe2x80x9d), e.g., labels on soup cans, others are not. For example, some upper labels on bottles such as ketchup and beer bottles are not square cut.
When packages or labels are printed on the printing press, in order to increase efficiency they are typically printed in large numbers simultaneously on the medium. Furthermore, to minimize waste, the individual designs of packages or labels are repeated on the medium packed tightly together, preferably as closely as possible, and often abutting. We call such a set of repeating designs a xe2x80x9clayout.xe2x80x9d
A package or label is usually designed on a CAD system. ArtiosCAD from Barco Graphics, of Gent, Belgiumxe2x80x94the assignee of the present inventionxe2x80x94is a CAD system especially configured for packaging design. The system allows the design of the package geometry, and the inclusion of an image, also called graphics or artwork herein, into the package design.
Historically, a die is a metal instrument used to stamp out, or cut out, a final shape from the original media. These days, many different processes are used for cutting, including laser-cutting processes. The term die is now understood to mean the data that describes the cut out regions. When applied to packages or labels, the die is a contour that describes the shape of the package or label after cutting.
A mask is the geometric boundary of the design that will be printed. In packaging design, the mask of the image to be printed on a package is often defined relative to the die of the package. In one simple example, the mask may be a line 1 mm outside the die. Note however, that the mask need not follow the die outline. For example, many boxes contain flaps that do not contain any printing. The mask may fall inside the die outline for such a flap.
A xe2x80x9cdesignxe2x80x9d as used herein refers to the combination of the image of a package or label, and may include a single die. The word xe2x80x9cstationxe2x80x9d is sometimes used synonymously with what we call a xe2x80x9cdesignxe2x80x9d. A design or station is a single instance of a package or label. The die is associated with one or more images.
It is often desirable to have the imaged area (the area containing artwork) in a package or label be slightly larger than the xe2x80x9ctrimmedxe2x80x9d (i.e., cut) area. This is called bleeding, and the enlargement, i.e., the area by which the image is larger than the cutting outline, is called a bleed. Thus, for the example of the mask being a line 1 mm outside the die, we have a 1 mm bleed. Bleeding is done to compensate for any misregistration in the printing or in the cutting of the individual packages or labels. Without bleeding, the misregistration may lead to some of the areas in the package or label remaining unprinted, or the wrong areas being printed with the incorrect imagery. This in general is an undesired effect.
When the package or label designs are laid tightly packed on the medium for printing, the bleeds may overlap. These overlaps must be resolved to prevent the image from one package impression from incorrectly printing over another image of another impression.
The present invention is a method and apparatus for resolving overlaps in printing layouts that contain a plurality of possibly repeating designs. Each design includes at least an image. There is a mask that defines the border of printing the design. A design may also include a die defining a contour. Because these designs are typically packed tightly together on the layout in order, for example, to conserve material, there may be overlaps contained within at least two masks. It is thus needed to provide a method for preventing the image of one package or label design from incorrectly printing over another. By eliminating the possibility of such incorrect overlaps, the present invention would increase the efficiency of printing packages and labels, and would allow for a more economical use of the material onto which the designs are printed.
One embodiment of the present invention includes the following three steps: 1) identifying overlaps that may require adjustment decisions, 2) presenting this information to the user, for example by way of a Graphic User Interface (GUI), and 3) modifying the masks in the layout according to the response of the user to the information presentation step.
Resolving overlaps in printing layouts that contain repeating designs includes determining where overlaps occur. An embodiment of the present invention identifies overlaps and generates a list of none or more overlap records. A version of the present invention includes organizing these overlap records into a set of none or more groups such that all overlaps in the same group are similarly modified.
One of the possible modifications of any overlap of the images of two designs is visually reversing the order of the overlap. This preferably is implemented by cutting back one of the masks. Alternatively, it may be affected by reversing the order of layering in the layout. Another possible modification method is called the mask split method and includes, in one version, determining a line (a dividing line) between the two designs, for example, between the two dies, and adjusting the masks of one or both designs to not extend beyond the determined dividing line, such that any bleed between the two dies extends only as far as the determined dividing line between the two dies. The dividing line preferably is the medial axis, i.e., the bisecting line midway between the two dies.
The purpose of the first step then is twofoldxe2x80x94to recognize and list all possible overlaps, and to organize this information in a second list according to shared attributes.
The preferred embodiment includes a second step wherein these lists of overlap records are displayed to the user, preferably by means of a Graphic User Interface (GUI), along with a set of one or more possible modifications of the designs in the overlap. As described above, the possible modifications include reversing which design of the overlap appears on top of the other design, and the mask split method. Either of these methods is implemented in the preferred embodiment by adjusting one or both of the masks.
An additional step for resolving overlaps in printing layouts is to modify the designs according to the decisions made by the user in the previous step, or, in some embodiments, automatically. In the version that includes presenting the possible modifications to the user, the user manually inputs to the computer system none or one of the set of possible modifications. Subsequently, any necessary modifications to the designs in regions of overlap are made according to the edited decisions input by the user.
According to an improved implementation, for each overlap record displayed to the user, preferred modification is displayed with the set of possible modifications. Failure by the user to input a decision leads to the preferred modification being carried out.
According to another version of the invention, a method is described for resolving overlaps in printing layouts that contain a plurality of possibly overlapping designs that includes determining any regions of overlap in the layout, and, for each determined overlap region, deciding whether or not to modify the overlap region and, if modification is decided, selecting a mask modification. The selection and deciding may include presenting a set of possible modifications to the user. The selection and deciding may also be according to a modification criterion, and then be carried out automatically without further user intervention, or include user intervention. The method modifies the layout related to the region of overlap according to the results of the previous decision. That is, for each determined region of overlap, this method decides whether or not to modify the overlap. A mask modification method is then selected ifxe2x80x94based on a modification criterionxe2x80x94modification of the overlap is chosen. The method makes the necessary modifications as dictated by the decisions and selected methods arrived at in the previous step.
As above, this method further includes the grouping of any regions of overlap into a set such that all the overlaps in the same group are similarly modified. The possible modifications are the same as those described in the previous method (i.e., reversing the overlap of the two designs, or determining a dividing line, e.g., the medial axis between the two dies of the design and adjusting the mask of each design accordingly).
One example of the kind of decisions and resulting modifications that might be made by this method concerns the printing of flaps and main panels. According to an embodiment applicable to the design of packages that may include a plurality of main panels and none or more flaps, the method includes identifying the parts of the packages in each overlap region. The modification criterion includes that the bleed of a main panel may overlap a flap, that a flap may overlap another flap, that a flap may not overlap a main panel, and that the mask split method is applied when the bleed of a main panel overlaps another main panel. In an alternate embodiment, the mask split is applied to an overlap of two flaps. In yet another embodiment, the modification criterion includes comparing the colors of the images in an region of overlap. For example, in accordance to one implementation of such an embodiment, the image of a main panel may overlap a flap, and a flap may overlap another flap. The bleed of a flap""s image, however, may or may not be allowed to overlap a main panel depending on the colors of the flap image and the main panel image. The criterion includes that if the colors of the flap and the main panel are the same, then the overlap is permitted. The criterion further includes that if there is an overlap between two printed flaps and the colors differ, then the mask split method is used. According to another embodiment, the criterion includes that a flap that has a visibly printed area may overlap a flap on which nothing is being printed. Yet another criterion version includes that a flap that has a visibly printed area may not overlap a flap that includes a xe2x80x9ckeep awayxe2x80x9d(non-print) area.
Once a modification criterion has been established, this method carries out the necessary modifications. In one version, the decided and other possible modifications are presented to the user prior to being carried out. In another, the modifications are carried out automatically.
Another version of the present invention is an apparatus for resolving overlaps in a layout including a plurality of possibly overlapping designs. This apparatus comprises a computer, including a means of inputting the layout. The computer is programmed to determine regions of overlap. The apparatus further comprises a user interface to the computer system including a display showing the overlap regions and a set of one or more possible modifications of the designs in the overlap regions and, similarly, one or more possible modifications to the regions of overlap. This apparatus also comprises a user interaction mechanism for a user to input a selection of none or one of the sets of possible modifications for any overlap region. The computer is programmed to modify the layout related to each region of overlap according to the user selection.
The method and apparatus for resolving overlaps in a layout including a plurality of possibly overlapping designs would allow, then, for both manual (i.e., based on user input) and automatic (e.g., based on a modification criterion) modifications of the designs in the overlap. The user would either make editorial decisions based on organized lists of overlap records provided by the initial, pre-GUI, stage of the process, or would rely on the automatic correction of any possible overlap conflicts as determined by a modification criterion. In either case, the occurrence of undesirable overlaps would be eliminated, resulting in a more efficient use of material and in the significant improvement of the printing of package and label designs.